Edward weston



' (No Model.)

, E. WESTON.

, ABSORBENT FOR ELECTRIC LAMPS. I

110.255.3622. Patented Mar. 21,1882.

Nr'rn STATES EDW'ARD WESTON, OF NEWARK, NEW JERSEY, ASSlGNCR TO THE USITED STATES ELECTRIC LIGHTING COMPANY, on NEW YORK, N. Y.

A BSORBENT Foe eteiornio LAMPS v1 SPECIFICATION forming part of LettersPatent No.

ceases, dated March 21, 1882.

Application filed October 17, 18 81. (No model.)

ing is a specification.

The lamps to the manufacture otiwhich this my present invention relatesare those in which a conductor of carbon or similar substance isused,tbe said conductor being mounted on metallic wires sealed into atransparent receiver from which the air has been as far asposs'ibleexhausted.

The objectot' the sa diuvention is to faciliu.

' tate the withdrawal of an comma-tubes, and

to produce therein a inafter specified,

' another application I have set forth a plan for higher vacuum than hasheretofore been attained, and this Iefl'ect by the employment, undercertain conditionshereof the oxide of thorium. 1n

utilizing such a substance, consisting substantially in placing in eachlamp a small quantity of the oxide of thorium, which under propermanipulation absorbs with great avidity the residual air of an imperfectvacuum. In this waya highvacuum is maintainedin the globes.

quantity ot'this This object I have found may be attained'in another andmore economical manner by connectiug a bulb or retort containinga propersubstance with the air-exhaust apparatus, heating it, and thenallowingit to cool after the process of withdrawing the air has beencarried to the usual point, and the portion of the apparatus to whichthe lamp and the retort are connected cut oft" from the pump.

-In this way a number of lamps may be simulin the apparatus employedtaneously exhausted, and then detached in the usual manner and sealed.In this process and in the conduct ,,thereot lie thy-presentimprovements. The

substance thoria or thorina,which.[ utilize for thispurpose, is the onlyknown oxide of thorium-oneot' the earthmetals. The preparation ofthorinafrom minerals containing thorium may be efi'ected in variousways, according to thenature of the substances with which it isassociated, From thorite it tion contains the thorium,

- extending therefrom,

heated by means of a spirit-lamp.

may be separated verized ore with hydrochloric acid, evaporating todryness, digesting the residue with weak acid in order to separate thesilica, filtering,-

and treating the solution with snlphydric acid The resulting solutoseparate leudvand tin.

which may be precipitated as a hydrate by ammonia, and the precipitateignited, The resulting product is oxide of thorium, which maybe used inthe manner directed. Should much iron, mangan- 6o use, or uranium bepresent, these bodies may be separated by redissolving-the hydrate inweak hydrochloric acid, andthe thorium precipitated aspotassio-thorinicsulphate by treatmeut'witl a; botsaturatedsolntiou ptneutral potassi' suiphateTThe precipitate thus obtained is dissolvedinhot water andtreated with ammonia, and the resulting precipitateignited, as before, Tlioria, when used as above described,is a powerfulabsorbent of the re- 7o sidual gas in an imperfect vacuum, and as suchforms a valuable element in the manufacture of durable incandescentlamps.

The drawing hereto annexed illustrates a simple device forsimultaneously exhausting a 7 5 number of lamps according to the methodproposed The apparatus, composed entirely of glass,consis'tsot' a mainstem, A, with branches and represented by B; The stem A is arrangedsuitable v exhaust apparatus, and contains a stop-cock, E, by means ofwhich communication with the pump is cut off. At a convenient poin talong the stem is connected, permanently or detachably, a retort, properquantitymt' thorina. One or any desired number of lamps, D D, are weldedto the branches B by sealing-tubes C- 0. To exhaust the lamps the plug Eis turned to establish communication with the air-pump. The air is gothen withdrawn as perfectly as possible, the thorina in the retort 13being at the same time The stem A is then cut 05 by the stop-cock fromthe pump, and the thorina allowed to cool, after 5 which the lamps aredetached by heating the stems O and twisting them off. This apparatus istypical of others, which may be employed by treating thetinely-pnl- 50for attachment to a F, containing a Paten t, is-

for the; same purpose, so that I would not be understood as confiningmyself to its use in carrying out my process.

' I am aware that substances such as charcoal have been employed for thepurpose of absorb ing the gases driven ofl' from the carbon con doctorsin the manufacture of lamps. This I do not claim herein.

Having now described my invention, what I- claim as new, and desire tosecure by Letters 1-."The improvement in the manufacture of incandescentelectric lamps which consists in firstexhausting mechanically the globesas

